<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>

<body>
  <div id="app">
    <div>
      <div v-for="(item,index) in arr":key="item.id"
        style="display: inline-block"
      >
        <input :value="item" v-model="all" type="checkbox"  />
        <span>{{item}}</span>
      </div>
      <p>你选中的元素, 累加的值和为:{{toatl}}</p>
    </div>
  </div>
  <script src="./vue.js"></script>
  <script>
    const app = new Vue({
      el: '#app',
      data: {
        arr: [9, 15, 19, 25, 29, 31, 48, 57, 62, 79, 87],
        all:[],
        toatl:0
      },
      watch: {
        all(newValue){
          this.toatl = this.all.reduce((sum,item)=>sum + item,0)
        }
      },
	
	  
    })
  </script>
</body>

</html>